Method of producing sisal fiber and wax



ATTORNE Y5 Aug. 25, 1953 P. F. BRUINS METHOD OF PRODUCING SISAL FIBER AND WAX Filed April 5. 1949 Patented Aug. 25, 1953 2,649,624 METHOD DEPRODUCING SISAL FIBER, AND WAX 'Fiiuh'detib'fi, Ih'i, NewYork, N. Y.; a corporation of New York Kfihaiidh Kpfil 5, 1949, sril $23,454

7 'C'Iaiiiis.

My nve ti elates .t "s t ,v method of separating sisal We)? I 7 v fire a A new a and, 'imprjojvfed method gr; paratm'g the sisal fiber from the s'i'sdl leaves, am a new 'aln'd improved sisal wax.

b meehsl et sndmm and thus re leave s 'Ihe lea fe .fro

@ f meme/Kim fs ,ij aqueous "separated ulp; w

saiid soft and s'nieary tvzmes" and said coldr bod1e is of 311; amerphous structure. v

According to my new and improved m th lalile's} The; lelaff thus lie" suhstzirii'tii y an; of its 01" it is tr ated. err i l ir s v has its 'dr igiril 'stlijifitu're bf tiulp, fibre. I contact the legi Wh' and Wh l i 1 55 $51 9 all or substantially 511. H

tially anhydrous. H andpreferablyi v stantially immil'se perchlorethylene ca, chlorinated hydrofcd' ..The formula of t CI-ICICClz. It has a b ling o C The formula of j ei 'ehlpl et yler e also Ides nated as tetrachlolqethyih, is 00150015. It has a boiling point 'df 121f CL 1 The formula pf esrpdh ,te

liquid so'li'ient, which is opti ghd prefefehiy heated to a suitable teiiibeigdture whi ch may be closeto its boiling pgint, but I prefer t6 use the solvent in yapo1- f6jrm.,

The sisal leaf, whileseiid l'eef has its g 'igipel structure, my, b i h tecfi de w t the, s l.- v v por or liquid i a 9128 1 .tenkip x easel, whose pressure is that of the external atmos h 9 e 1i itvh nitswori iiua structure, ay he thus \yiththe qappr; ized s l t h liq id 9 E1 .s asite k or vessel, which he early desired internal pressure eith"er above 1: pelow sta derdgtmospheric pressure of millimeters 1f ne'i cury I p r ii in i 'gn' tank. Q ".31s u; :h;as a; tank oi'yes'sl ep'eh at its tpp whiph eontains a pool of the liquid sjqiigentat its bottom and a heate for heating ahd apori gi g the solvent, so that its fil R nk Q .vesse we selected height, below tpp ef the tank aboye the liquid solvent. Thls tlahk gi yessel is egpledat it's top pert, semen theyaporized sgl veht ,cgn: denses intd liquid gt. suiteble eight; .an.d .the liquid sdlveht dibiis back irito the pool of liquid solvent. i I imm r e h 1??? ibehy m eq. So vent. during a, suitable exti tien periqd, Thus-ii ,I use Vapbqz'd triehloylehe, the extraction peried is b1323 0 tiyp es. Du ing the, 'xtr'ei'tibh fi'e'riid, the vapor of the solvent con-- denses on the sisal leaf, due to the high Water content of the sisal leaf. I prefer to use a solvent whose boiling point is below 100 C., so that the vaporized solvent produces little or no vaporization of the Water of the sisal leaf during the extraction. The solvent vapor thus con-i denses into liquid solvent on the sisal leafjand the liquid solvent dissolves the sisal ,wax. This liquid solution of the sisal wax drops back into the pool of liquid solvent at the bottom of the vessel.

At the end of the extraction period, all or substantially all of the sisal wax is removed from the sisal leaf, and such leaf retains the sisal fibre and all or substantially all of the original pulp, including the water of the pulp. The improved method therefore does not substantially extract the soft and smeary waxes and the color bodies of the aqueous pulp.

Due to the thickness of the sisal leaf, such leaf is not heated through-and-through to the temperature of the vaporized solvent. Thus, if I use vaporized trichlorethylene at or a little above its boiling point of 867 C., I estimate that the average through-and-through temperature of the sisal leaf is substantially 49 C. The outer surface of the leaf is heated to a higher tem perature than its interior.

While the sisal leaf is thus being dewaxed, it is held vertical or inclined, so that the condensed solvent and its dissolved sisal wax can drip readily off the leaf. There is no loss of solvent in the extraction tank, because its vapor is condensed below the top of the tank.

The leaf becomes limp and softer, due to the treatment thereof. At the end of the dewaxing period, it is free or substantially free from the solvent, because the condensed solvent drops continuously off the leaf.

I then pass the dewaxed and heated and limp sisal leaf immediately to the scraping or decorticating wheels or drums, which remove the sisal fibre in the usual manner While the leaf is hot and limp. Due to the dewaxing and the elevated temperature of the limp sisal leaf, it requires less vigorous mechanical working to remove the sisal fibre. The tensile strength of the sisal fibre is thus improved.

I thus secure an initial or crude sisal wax which has a chocolate-brown color, which is much lighter in color than the crude sisal wax secured according to the old method. This crude sisal wax is substantially free from objectionable impurities which are retained in the aqueous pulp, because I treat the leaf while it has its uncrushed aqueous pulp. As compared with 50% by weight of resin impurity and 5% by weight of fat and oil impurity in a crude sisal wax made according to the old method, the improved crude sisal wax usually has a maximum of 25% by weight of these impurities. By reason of the relatively light color of the improved crude sisal wax, and its relatively high purity, such improved sisal wax can be used for many purposes without any additional treatment, and it can be refined and decolorized if desired, at relatively low cost. For example, this initial or crude sisal wax can be used without additional treatment in shoe polishes, fioor polishes, carbon paper, etc., as a substitute for carnauba wax,

As another marked advantage, the initial or crude sisal wax which I produce, is free from certain dark color impurities which are extracted from the dry sisal pulp according to the old method. These objectionable dark impurities 4 cannot be removed by the known decolorizing methods.

Hence the refined sisal wax which I produce from the initial or crude sisal wax, has a much lighter color than the refined sisal wax made from crude sisal wax which has been extracted according to the old method. The refined sisal wax made from the improved crude sisal wax, can be used as a substitute for the highest grades of carnauba wax and other waxes for many purposes.

It is well-known to degrease metal objects by contacting them with the vapor of trichlorethylene and other fat solvents, and apparatus for this purpose is well-know and hence requires no specific description herein. Such apparatus is disclosed, for example, in Dinley U. S. Patent No. 2,036,261; Dinley U. S. Patent No. 2,028,759; Wolff U. S. Patent No. 1,171,698; Robertson U. S. Patent No. 1,907,875; and Robertson U. S. Patent No. 1,911,928.

Fig. 1 is a microphotograph of the initial or crude sisal wax which is produced according to my method, prior to. subsequent refining or decolorizing or bleaching. This microphotograph represents a magnification of 250 diameters and it was taken by transmitted light through a thin layer of said sisal wax, which was deposited on a glass slide from a solution of said sisal wax in carbon tetrachloride. This microphotograph shows a definite crystalline structure of' the initial or crude sisal wax which is produced according to my method, prior to any subsequent refining or decolorizing or bleaching;

Fig. 2 is a microphotograph similar to Fig. l, which illustrates the structure of the initial or crude sisal wax which has been produced according to the old method. Fig. 2 indicates an amorphorus structure.

Fig. 3 is a photograph whose left picture shows the color of a film of initial or crude sisal wax made according to the old method, and whose right picture shows the color of a film of initial or crude sisal wax made according to my method, prior to any subsequent refining or decolorizing or bleaching. These-photographs were taken of thin layers of the respective sisal waxes, which were deposited on respective glass slides by dipping the respective glass slides into the respective molten waxes. It is clear that the improved crude or initial sisal wax made according to my method, prior to refining or decolorizing or bleaching, has a much lighter color than the corresponding crude or initial sisal wax which has been made according to the old method; and

Fig. 4 corresponds to Fig. 3 save that the layers of the respective sisal waxes were deposited on glass slides from a solution of the respective initial or crude sisal waxes in carbon tetrachloride. As also indicated in Fig. 3, the improved crude or initial sisal wax made according to my method, prior to subsequent refining or decolorizing or bleaching, has a much lighter color than the crude or initial sisal wax made according to the old method.

Specimens of these microphotographs are attached to and made a part of this application.

Separation of crude sisal was: from the solvent The initial or crude sisal wax has a melting point of -90 C. As the pool of solvent in the bottom of the extraction tank or vessel takes up the sisal wax, the solution of sisal wax reaches a selected concentration. The solution is rem ved cont nuously or in batches from the pooL said solution is filtered to remove dirt and other suspended solids, and said solution is led through a conventional vaporizing and solvent-recovery mechanism. In this mechanism, the solvent is vaporized and thus separated -from the dissolved sisal wax. The separated and pure vaporized solvent is then condensed and led back to said pool of solvent.

The temperature of this mechanism is above the melting point of the initial or crude-sisal wax, which is thus recovered in molten form, from which it is allowed to solidify. This solidified crude sisal wax can be subjected, if desired, to one or more additional steps Decolorizing the crude sisal wax EXAMPLE 1 5 parts by weight of activated decolorizing clay and 1 part by weight of activated decolorizing carbon are added to 100 parts by weight of the initial or crude sisalwax, which is maintained at a temperature of 100 (Jr-150 C. The mixture is agitated for 30 minutes to one hour, maintaining said temperature.

The decolorized sisal wax is then separated in molten form from the clay and carbon by filtration or other means.

EXAMPLE 2 The decol'orizing agent is lignin, of the type which is recovered in the kraft paper process. In this kraft paper process, chipped wood is cooked under pressure with a mixture of caustic soda and sodium sulfide. The resultant cook liquor is acidified 1J0 IGOOVGI" the lignin. Five parts by weight of such lignin is mixed with 100 parts by weight of the crude molten sisal Wax at 130 (1-140 0., and the mixture is agitated at said temperature for one hour.

The resultant mixture is then treated according to Example 1.

These decolorizing methods use decolor'izing agents of the adsorbing type.

The above decolorizing stepsp'rooluce a sisal wax which has a brown to tan color which is much less dark than in the initial crude wax. since I do not extract objectionable dark coloring matter from the dry pulp of the sisal leaf according to my method, this decoloriz'ing produces a wax of much lighter color than when the initial crude sisal wax is made according to the old method.

Bleaching or chemical decolo'rizing For this purpose, I can use sodium hypoohlorite, bleaching powder, organic peroxides such as benzoyl peroxide, inorganic peroxides, sulfuric acid, other acids, and other chemical bleaching or decolorizing agents.

I can use these chemical agents before or after treatment with the activated clay, activating carbon, and other adsorbing decolorizing agents.

Removal of fats and oils from the crude sisal well:

After the crude sisal wax has been separated from the solvent, such Wax is passed infinely divided form into a pool of anhydrous acetone which is kept at a temperature of 25 C., with constant stirring. The crude sisal wax may be in finely divided solid form when it is added to the acetone. The crude sisal wax may be in molten form, and it is added slowly to the pool of acetone to be solidified in fine particles in said pool. The acetone dissolves the fats and oils of the crude sisal wax, without dissolving the" as above described.

6 sisal wax or ipurity. For this pur pose I can use other selective solvents at oi'roin'a'ri room temperature of "20 C.=25 'G. such higher boiling ketones, diethyl ether, and other higherboiling point others.

I optionally prefer to remove the rat and oil impurities from the crude sisal wax, before removing the resin impurities The partially purified sisal is separated from the selective solvent 'by nltration, centrifug mgr, settling, or other sliitable method.

Removing resin impurities .from the crude sisal wax, after remooinp the fat and Oil impurities The sisal wax is soluble in not alcohols, such methanol, ethanol, isopropanol, other suitable uionohycrio alcohols and other solvents, in whieh the resin impurity is insoluble. v

The partially purified sisal is mixed with the selective solvent at suitable temperature, such as 50 C}, if methanol is used in order to dissolve the sisal was, without dissolving the resin. The solution of the sisal wax in the solvent is separated fr m the undissol'veu resin, and the solu*- tion of the sisalwaifz is cooled to 20 0.4530. or below, to eparate the sisal wax from the solvent.

The residual solvent in the purified sisal is driven off.

I can treat this purified 'al with the adsorbing and chemical decolorizing agents, and this is preferred.

Microscopic observation fails to show any difference in structure 'lietii ejeii sisal fibre separated from the Sisal leaf accor ing to my method, as compared with the 616. method.

Tensile tests have shown that an improved sisal fibre is produced by deoorticating the dewaxed sisal leaf.

Old Method New Method Fibre from Fibie ironi Uiitieated Dew'axed Sisal Leaves; Sisal Leaves,-

Granis Grains L Tens Strength of the F Fibre SS6 931 Tensile Strength 0! he Lower I 1,122 l, 182 Tensile strength of the Middle Third. 1,133 1, 242 Tensile Strength or the Upper Third 770 736 if a crude sisal wax which has been produced according to the old method, is subjected to the above-mentioned deeolorizirig agents as above stated, the resultant sisal is much darker in color than when the starting iiiaterlal is a crude sisal wax produced according to method. This is because the solvent extracts certain black lin urities from the dry pulp, which the solvent does not; extract from the aqueous pulp. The improved deoolorized sisal wax is therefore substan'tlally free from the dark im urities or dry sisal pulp. 4

improved sisal wax retains its crystalline structure, the improved sisal wax is treated I have desoi ioed a preferr d embodiment of my invention, but numerous changes and omissions and ad itions and subs motions be made without departing from its scope.

I' claim:

i s 'rnetliodor separating sisal wax from a sisal leaf, which: consists in contacting the surrage of said leaf with a solvent or sisal and extraot'in and dissolving the al was of said leaf irrsaid solvent and renio gsaid solution from said leaf, said leaf teing thus contacted with said solvent and said solution being removed. from said leaf while said leaf has itsfibre and also has its aqueous pulp in uncrushed form, said solvent extraction being substantially confined to said surface to retain in said uncrushed aqueous pulp substantially all of its wax and color bodies which are soluble in said solvent.

2. A method of sesparating sisal wax from a sisal leaf, which consists in contacting the surface of said leaf with the vapor of a solvent of sisal wax, condensing said vapor in liquid form on said surface and extracting and dissolving the sisal wax of said leaf in said condensed liquid solvent and removing said solution from said leaf, said leaf being thus contacted with said vapor and said condensed liquid solvent and said solution being removed from said leaf while said leaf has its fibre and also has its aqueous pulp in uncrushed form, said solvent extraction being substantially confined to said surface to retain in said uncrushed aqueous pulp substantially all of its wax and color bodies which are soluble in said solvent.'

3. A method of separating sisal wax from a sisal leaf, which consists in contacting the surface of said leaf with a solvent of sisal wax and extracting and dissolving the sisal wax of said leaf in said solvent and removing said solution from said leaf, said leaf being thus contacted with said solvent and said solution being removed from said leaf while said leaf has its fibre and also has its aqueous pulp in uncrushed form, said solvent extraction being substantially confined to said surface to retain in said uncrushed aqueous pulp substantially all of its wax and color bodies which are soluble in said solvent, said solvent being substantially immiscible with water.

4. A method of separating sisal wax from a sisal leaf, which consists in contacting the surface of said leaf with the vapor of a solvent of sisal wax, condensing said vapor in liquid form on said surface and extracting and dissolving the sisal wax of said leaf in said condensed liquid solvent and removing said solution from said leaf, said leaf being thus contacted with said vapor and said condensed liquid solvent and said solution being removed from said leaf while said leaf has its fibre and also has its aqueous pulp in uncrushed form, said solvent extraction being substantially confined to said surface to retain in said uncrushed aqueous pulp substantially all of its wax and color bodies which are soluble in said solvent, said solvent being substantially immiscible with water.

5. A method of treating a sisal leaf, which consists in contacting the surface of said leaf with a solvent of sisal wax and extracting and dissolving the sisal wax of said leaf in said solvent, said leaf being thus contacted with said solvent while said leaf has its fibre and also has its aqueous pulp in uncrushed form, said solvent extraction being substantially confined to said surface to retain in said uncrushed aqueous pulp substantially all of its wax and color bodies which are soluble in said solvent, and then decorticating said leaf while crushing its aqueous pulp.

6. A method of treating a sisal leaf which consists in contacting the surface of said leaf with the vapor of a solvent of sisal wax, condensing said solvent in liquid form on said surface and extracting and dissolving the sisal wax of said leaf in said condensed solvent and removing said solution from said leaf, said leaf being thus contacted with said vapor and said condensed solvent and'said solution being removed from said leaf while said leaf has its fibre and also has its aqueous pulp in uncrushed form, said solvent extraction being substantially confined to said surface to retain in said uncrushed aqueous pulp substantially all of its wax and color bodies which are soluble in said solvent, and then decorticating said leaf while crushing its aqueous pulp.

7. A method of treating a sisal leaf, which consists in contacting the surface of said leaf with a solvent of sisal wax and extracting and dissolving the sisal wax of said leaf in said solvent, said leaf being thus contacted with said solvent while said leaf has its fibre and also has its equeous pulp in uncrushed form, said solvent extraction being substantially confined to said surface to retain in said uncrushed aqueous pulp substantially all of its wax and color bodies which are soluble in said solvent, and then decorticating said leaf while crushing its aqueous pulp, said solvent being heated to a sufficiently high temperature to make said leaf hot and limp at the end of said extraction, said leaf being hot and limp when the decortication of the leaf is begun.

8. A method of treating a sisal leaf which consists in contacting the surface of said leaf with the vapor of a solvent of sisal wax, condensing said solvent in liquid form on said surface and extracting and dissolving the sisal wax of said leaf in said condensed solvent and removing said solution from said leaf, said leaf being thus contacted with said vapor and said condensed solvent and said solution being removed from said leaf while said leaf has its fibre and also has its aqueous pulp in uncrushedform, said solvent extraction being substantially confined to said surface to retain in said uncrushed aqueous pulp substantially all of its wax and color bodies which are soluble in said solvent, and then decorticating said leaf while crushing its aqueous pulp, said vapor being'at a sufficiently high temperature to make said leaf hot and limp at the end of said extraction, said leaf being hot and limp when the decortication of the leaf is begun.

9. A method of decorticating a sisal leaf which has its aqueous pulp in uncrushed form, which consists in heating said leaf to at least substantially 50 while removing the sisal wax from said leaf by surface solvent extraction to produce a hot and limp sisal leaf which has substantially all of said aqueous pulp in uncrushed form, and then decorticating said leaf while it is hot and limp by scraping said leaf under pressure while crushing said aqueous pulp.

PAUL F. BRUINS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,048,719 Whitford July 28, 1936 2,372,561 Elgin Mar. 27, 1945 2,428,813 Rhodes et a1 Oct. 14, 1947 2,449,107 Broeg et al Sept. 14, 1948 FOREIGN PATENTS Number Country Date 575,642 Great Britain Feb. 27, 1946 OTHER REFERENCES Politzer Waxes From Sisal Waste, Chemistry and Industry, June 26, 1948, pages 408-409. 

1. A METHOD OF SEPARATING SISAL WAX FROM A SISAL LEAF, WHICH CONSISTS IN CONTACTING THE SURFACE OF SAID LEAF WITH A SOLVENT OF SISAL WAX AND EXTRACTING AND DISSOLVING THE SISAL WAX OF SAID LEAF IN SAID SOLVENT AND REMOVING SAID SOLUTION FROM SAID LEAF, SAID LEAF BEING THUS CONTACTED WITH SAID SOLVENT AND SAID SOLUTION BEING REMOVED FROM SAID LEAF WHILE SAID LEAF HAS ITS FIBRE AND ALSO HAS ITS AQUEOUS PULP IN UNCRUSHED FORM, SAID SOLVENT EXTRACTION BEING SUBSTANTIALLY CONFINED TO SAID SURFACE TO RETAIN IN SAID UNCRUSHED AQUEOUS PULP SUBSTANTIALLY ALL OF ITS WAX AND COLOR BODIES WHICH ARE SOLUBLE IN SAID SOLVENT.
 9. A METHOD OF DECORTICATING A SISAL LEAF WHICH HAS ITS AQUEOUS PULP IN UNCRUSHED FORM, WHICH CONSISTS IN HEATING SAID LEAF TO AT LEAST SUBSTANTIALLY 50* WHILE REMOVING THE SISAL WAX FROM SAID LEAF BY SURFACE SOLVENT EXTRACTION TO PRODUCE A HOT AND LIMP SISAL LEAF WHICH HAS SUBSTANTIALLY ALL OF SAID AQUEOUS PULP IN UNCRUSHED FORM, AND THEN DECORTICATING SAID LEAF WHILE IT IS HOT AND LIMP BY SCRAPING SAID LEAF UNDER PRESSURE WHILE CRUSHING SAID AQUEOUS PULP. 